Protect against various FD_SETSIZE restrictions. Note that I couldn't

really test this well -- because libc5 linux systems just don't let you
muck with FD_SETSIZE easily.  Folks on BSD systems should be able to
-DFD_SETSIZE=16 or 20 and produce lots of interesting failures.

Clean up make_sock error messages a bit.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@80645 13f79535-47bb-0310-9956-ffa450edef68